Production methods for fibrous material are known, in particular for paper webs or cellulose sheets. They generally consist of pouring a mix of fibrous material and water onto an endless conveyor belt in movement. Here the mix is progressively deprived of its water content and subjected to a series of traditional processes which finally lead to the obtaining of a paper web or, in more general terms, to the obtaining of a web of fibrous material, to be then wound into rolls for subsequent uses.
The production of fibrous webs, in particular papers of the most varied type, requires the use of many types of chemical products as additives to give the different paper types particular properties, or to facilitate the process.
These products are either added directly to the initial fiber suspension (to the cellulose pulp in the case of paper) or are applied onto the surface of the fibrous web under formation by methods known to the expert of the art.
In the first case, part of the additives is lost during the initial fiber draining stage on the flat table, to create problems of recovery and disposal of the liquid effluent, and of obtaining the correct targeted concentration of added product relative to the fibers.
In the second case, penetration of the additives into the centre of the sheet becomes difficult and there is greater lack of uniformity along its thickness.